A side shift backhoe in general is composed of a main transverse frame that has some type of retractable legs for ground support and when retracted the frame is carried on one end of a tractor. The transverse frame normally has upper and lower horizontal tracks extending substantially the full width of the frame. A backhoe supporting slide frame is carried on the tracks. One of the difficulties in providing such a slide frame and transverse frame lies in the ability to lock the slide frame in any given position while with the same structure having the ability to relatively freely slide the slide frame along the tracks.
One method used for providing the sliding and locking action is through the use of a chamfered surface on the upper track and normally on the upper edge or surface thereof and a chamfered surface on the lower track and normally on the lower surface thereof. The slide frames have hook portions that extend over the upper track and under the lower track. The hook portions have matching chamfered surfaces for engaging the chamfered surfaces on the respective tracks. Small hydraulic cylinders are provided on the slide frame and are used to force a separation between the slide frame and tracks so as to tighten or create a wedge like action between the chamfered surfaces.
One of the problems with the afore-mentioned structure is that when the hydraulic cylinders are released, the slide frame still has two chamfered surfaces engaging two chamfered surfaces on the transverse frame. Although, there is not the strong wedging action that is created when the hydraulic cylinders are extended; nevertheless, when it is a desire to slide the slide frame into a new position, it is often very difficult since the chamfered surfaces tend to create binding between the surfaces. Also, the upper chamfered surfaces carry almost the entire weight of the backhoe and the slide frame which creates a strong wedging action between these surfaces.
With the above in mind, it is the primary object of the present invention to provide a transverse frame and a slide frame in which the wedging action occurs only along the upper track on the transverse frame and generally in the area of the top surface of the track. At the upper track, the slide frame is provided with a part that extends over the edge of the track and has a downwardly inclined surface that engages a matching chamfered surface on the track. Hydraulic cylinders are placed so that upon extension they force separation of the two frames. This causes interaction between the inclined surface on the slide frame and the matching chamfered surface on the transverse frame so as to raise slightly the slide frame. When the cylinders are relaxed, the chamfered and inclined surfaces have the opposite effect and the slide frame is permitted to drop. With respect to the lower track, the slide frame has a plate like member with a horizontal surface that fits over the upper horizontal edge of the hozizontal track and engages that edge only when the slide track is lowered through retracting the cylinders. Thus, when it comes necessary to slide the slide frame relative to the two tracks on the transverse frame, there is a set of horizontal engaging surfaces and it is relatively easy to move the slide frame. Even though the upper incline surface is in engagement with the chamfered surface, the main weight of the sliding frame and backhoe are on the horizontal engaging surfaces at the lower track. Therefore, there would be very little if any binding between the slide frame and the transverse tracks as the slide frame is shifted along the tracks. Binding, particularly between chamfered surfaces often occur due to tilting of the slide frame and is minimized by the engagement of the two horizontal surfaces along the lower track.